There has been much debate over the last week as to how the forthcoming Windows Server 2008 release from Microsoft will embrace Linux, specifically with regard to the interoperability between Windows and Linux as evidenced by Release Candidate 1 code.
The two sides of the story seem to be either:
Windows Server 2008 Hyper-V Beta is built upon Xen source code, a project partially funded by Microsoft, so Linux interoperability is a given. Xen will be a core part of Hyper-V, and when you run a Linux Virtual Machine calls to Xen will be translated into Hyper-V hypercalls. Hyper-V is integrated at the service level in Windows Server 2008 rather than being a hosted platform, ipso facto Linux interoperability gets the edge and VMware gets edged out on the back of this value for money equation.
Hyper-V has an architecture that bears more of a resemblance to Xen than it does to something like ESX Server for example. Xen itself runs as a guest within the parent partition, nothing more and nothing less, and certainly any suggestion that there is a similarity between the Linux kernel paravirtualisation for Xen and Hyper-V is wishful but blinkered thinking.
At the end of the day the question that needs to be asked is whether anyone seriously believes that Microsoft would stuff some open source code within the Windows kernel?
The clever money would say not on your nelly.